Sensor using ultra thin waveguides and optical fibers

Abstract

Methods and apparatus are provided for detecting one or more contaminant particles in an environment with an optical sensor. The sensor includes at least one optical waveguide in a resonant arrangement and a light source positioned in an environment in which the presence of a contaminant particle is sought to be determined. The at least one optical waveguide is of a diameter that an evanescent tail of the lightwave extending there through extends into the environment and is reactive to at least one contaminant particle in the surrounding environment. A detector is positioned to receive light indicative of the sharpness of the optical resonance lineshape of the optical resonator at a pre-selected optical wavelength. The detected information determines the specific contaminant particle in the environment and the concentration of the contaminant particle in the environment.

1. An optical resonant sensor for sensing one or more contaminant particles in an environment, the optical resonant sensor comprising:
 a substrate; 
 a monochromatic light source operable to emit light on said substrate of a wavelength interactive with the one or more contaminant particles being sensed; 
 an input optical waveguide on said substrate having a receiving end positioned to receive the light emitted from the monochromatic light source and configured to allow the light to propagate there through toward an output transmission port; 
 an optical waveguide ring on said substrate and positioned to receive at least a portion of the light emitted from the monochromatic light source; 
 an output optical waveguide on said substrate and positioned to receive light from the optical waveguide ring and configured to allow the light to propagate there through toward an output transmission port; 
 a first detector configured to measure a resonance dip at the output transmission port of the input optical waveguide; 
 a second detector configured to measure a resonance peak at the output transmission port of the output optical waveguide; 
 wherein at least the input optical waveguide and the optical waveguide ring form an optical resonator in which that the evanescent tail of a lightwave propagating there through the optical waveguide ring extends into the environment in which the optical resonant sensor is positioned and is sensitive to a contaminant particle in the environment. 
 
     
     
       2. The optical resonant sensor of  claim 1 , wherein said substrate is one of a silicon substrate or a silicon-on-insulator substrate. 
     
     
       3. The optical resonant sensor of  claim 1 , wherein the environment in which a contaminant particle is to be sensed is air. 
     
     
       4. The optical resonant sensor of  claim 3 , wherein the contaminant particle is one of a chemical contaminant or a biological contaminant. 
     
     
       5. The optical resonant sensor of  claim 1 , wherein the optical sensor is a portable device. 
     
     
       6. The optical resonant sensor of  claim 1 , wherein at least one of the input optical waveguide and the output optical waveguide is formed as three-dimensional glass fiber. 
     
     
       7. The optical resonant sensor of  claim 1 , wherein the input-optical waveguide, the output optical waveguide, and the optical waveguide ring are photolithographically deposited polymer components formed on a semiconductor chip. 
     
     
       8. The optical resonant sensor of  claim 1 , wherein the input-optical waveguide, the output optical waveguide, and the optical waveguide ring are formed as silicon waveguides on a silicon substrate. 
     
     
       9. The optical resonant sensor of  claim 1 , wherein the light source is a single frequency laser.